Anonymous Snippets in UltiSnips
UltiSnips supports anonymous snippets: they are defined on the spot, expanded and immediately discarded again. They were requested by someone and Ryan implemented them, but I was all Meeeh because I didn't understand for what they could be used.
But I just realized they are in fact awesome: I have a new line in my RestructuredText Vim plugin file:
inoremap <silent> $$ $$<C-R>=UltiSnips_Anon(':latex:\`$1\`', '$$')<cr>
Hitting $ now directly translates into being in inline math mode. How cool is that?